Modern informed consent procedures have been shaped by several factors. First, the ethical doctrine of informed consent is derived from a western philosophic tradition that emphasizes individual autonomy and respect for persons. Second, federal regulations governing human experimentation have established specific requirements for the informed consent process. Little data exist, however, concerning what information and presentation style will help potential subjects to understand the purpose and methods of a research study and make decisions that reflect their authentic preferences and values. The focus of this study will be to describe the disclosure and decision making process and to identify how informed decision making can be achieved. To accomplish this objective, the investigators propose to conduct a study that will ask subjects what they believe is important in making research participation decisions; in addition, behavioral decision analysis theory will be used to identify factors and processes that are associated with better outcomes. Three distinct subject populations will be examined: l) adult cancer patients; 2) critically ill children; 3) Alzheimer's disease patients. The specific aims of this study are to: (l) examine and describe clinician-subject interactions during the consent process; (2) determine which factors are associated with informed decision making; (3) determine if there are different information and process needs for different subject populations; (4) update our understanding of the theoretical underpinnings of the informed consent process; (5) suggest alternative or modified mechanisms for enabling patients to make informed decisions about participation in research studies. This study will provide descriptive information about how informed consent is currently being obtained from potential subjects and will assess the different components of the decision making process to pinpoint which pieces are crucial to the ability of potential subjects to make informed choices about participation in a research study.